Analytical cohort and case-control studies are carried out in other countries with unique populations or data resources to examine risk factors for cancer. Record linkage studies of hospitalization and cancer registry data in Sweden and Denmark have revealed no excesses of breast or other cancers among women who had breast augmentation with silicone, and no excess of bone or connective tissue cancer among persons with metal hip replacements. Patients with hemochromatosis had notable excesses of liver cancer, those with ulcerative colitis had increased colorectal and hepatobiliary cancers, and those with systemic sclerosis had increased lung and non-melanoma skin cancer, whereas those with localized scleroderma had no cancer excess. Combined analysis of dietary data from four countries revealed that risk of renal cell cancer rose with increasing consumption of foods high in protein, fat, carbohydrates, and calories. Fried and well-done meats were associated with highest risk and increased risks were linked with low intake of vitamin E and magnesium, whereas protective effects were linked with consumption of orange and dark green vegetables. A case-control study of esophageal cancer in Shanghai, China demonstrated decreasing risk with increasing consumption of fruits, dark orange vegetables, and beef or mutton as well as with increased intake of protein, carotene, vitamins C and E, and riboflavin. Infection with human papillomavirus accounted for half of low-grade and 90% of high-grade cervical neoplasia in the relatively monogamous population of Taiwan, while infection with chlamydia trachomatis was independently linked with a borderline increase in high- grade but not low-grade neoplasia. A gastroscopic survey of 3,400 subjects in Shanghai, China in 1994, when compared with a baseline exam in 1989, revealed 31 new cases of gastric cancer. Compared to subjects with chronic atrophic gastritis, the relative risks of cancer were 7-fold higher for those with dysplasia and increased 3.5-fold for those with intestinal metaplasia. An intervention trial is being launched in late 1995 to inhibit precancerous lesions, based on treatment of Helicobacter pylori and supplementation with vitamins and a garlic preparation.